Edit ~/HW_files. Put the path to each filename and dirname you want to save in it, one file/dir per line, relative to the HW dir. For example, suppose HW contains files a, b, c and d and directories x, y and z, and z contains files za, zb, zc and dirs zx and zy. Suppose you want to save a, c, za and zx. You would put in the file